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Biomedical subjects

C P Flessel

Publications and source records attributed to C P Flessel.

12 recordsLinked to original sources
PubMed1990

Benzene, benzo(a)pyrene, and lead in smoke from tobacco products other than cigarettes.

Benzene, benzo(a)pyrene (BaP), and lead in mainstream smoke from cigars, roll-your-own (RYO) cigarette and pipe tobaccos were sampled to evaluate their potential health significance. Results with reference cigarettes were consistent with published values, providing support for the methodology employed. The emissions of benzene and BaP, expressed as mass emitted per gram of tobacco consumed, were similar for all products evaluated; for benzene, the mean values for cigars, RYO cigarette and pipe tobaccos were 156 +/- 52, 68 +/- 11, and 242 +/- 126 micrograms/g, respectively. Mean values for BaP were 42 +/- 7 and 48 +/- 4 ng/g for cigars and RYO cigarette tobacco, respectively. Lead values were below the limit of reliable quantitation in all cases. The mean benzene concentrations in a puff ranged from 1 to 2 x 10(5) micrograms/m3 for cigars, RYO cigarette and pipe tobaccos. For BaP, the puff concentration averaged about 60 micrograms/m3 for cigars and RYO cigarette tobacco. The results suggest that smoking cigars, pipes or RYO cigarettes leads to potential exposures which exceed the No Significant Risk levels of benzene and BaP set pursuant to California's Proposition 65. These tobacco products are now required to bear a health hazard warning when sold in California. We recommend that this be adopted as national policy.

Benzene↗
PubMed1986

Mutagenicity of fine (less than 2.5 microns) airborne particles: diurnal variation in community air determined by a Salmonella micro preincubation (microsuspension) procedure.

A simple modification of the Salmonella liquid incubation assay previously developed for detecting mutagens in urine was used to determine mutagenic activity of airborne particulate matter. The modification consists of adding ten times more bacteria (approximately 10(9) per incubation tube) and five to ten times less metabolic enzymes compared to the plate incorporation method. The mixture volume is approximately 0.2 ml, and the mixture is incubated for 90 min before pouring it according to the standard protocol. The modified procedure (micro preincubation or microsuspension) was approximately ten times more sensitive than the standard plate incorporation test for detecting mutagens in air particulate extracts and approximately ten to 31 times more sensitive for the chemical mutagens 2-nitrofluorene, 4-nitroquinoline-N-oxide, 2-aminofluorene, and benzo(a)pyrene in bacterial strain TA98. Mutagenic activity was detected in particle extracts obtained from 1 m3 of air (17 micrograms of extract) or less. This microsuspension procedure was applied to air particulate samples collected with low-volume (15-50 liters per min) virtual-dichotomous air samplers. Mutagenic activity was associated exclusively with fine particles (aerodynamic diameters of less than 2.5 microns). Diurnal patterns of mutagenic activity (TA98 revertants per cubic meter air) were investigated by measuring filter extracts from 2-hr samples collected in three San Francisco Bay Area cities during the summer or fall of 1982. Four criteria pollutants--lead, nitrogen dioxide, ozone, and sulfur dioxide--were simultaneously sampled at one location. Mutagenicity from fine particles sampled at this location was highly correlated with lead and much less correlated with nitrogen dioxide, ozone, and sulfur dioxide. The microsuspension procedure is applicable in testing samples of limited mass.

Air Pollutants↗
PubMed1984

Epidemiological monitoring of environmental lead exposures in California State Hospitals.

Blood lead screening of 8062 state hospital residents in California revealed 143 residents with excessive lead levels (greater than or equal to 30 micrograms/dL). This screening was part of the Childhood Lead Project and was performed in 1978. The purpose of this study was to identify "critical" lead sources in California State Hospitals. Accurate identification is crucial if subsequent abatement programs are to be effective. The strategy involved the following sequence of steps: 1) Selection of cases based on blood lead and erythrocyte protoporphyrin screening. 2) Determination of pica habits and environmental exposures through interviews with ward's staff and/or parents. 3) Measurement of lead levels in environmental samples reflecting exposures. 4) Interpreting these data in order to identify critical lead sources. 5) Reducing exposure to critical lead sources. 6) Following up of cases and controls to validate the effects of this strategy. A group of 36 lead-burdened cases with pica (30-60 micrograms Pb/dL blood) and 36 matched controls (PbB less than 20 micrograms/dL) were selected from among the developmentally disabled residents of two California State Hospitals. These subjects were studied in order to identify the lead sources to which they were exposed and to abate the major ones. Three major lead sources were found in the state hospitals: wall and furniture paints (100-45,400 micrograms Pb/g paint); surface soil (33-570 micrograms Pb/g soil); educational format was presented to all involved staff. The results have indicated a trend towards lower lead intake by the lead-burdened cases. In one of the two hospitals a "lead-free unit" had been established. All the lead-burdened cases were transferred to this unit in August 1981. A few months later the blood lead levels of all the cases dropped below 30 micrograms/dL. Initial epidemiological monitoring indicated where there were preventable hazards, which abatement efforts succeeded in reducing. Further monitoring of such problems is indicated in this and other developmentally-disabled populations.

Adolescent↗
PubMed1982

A rapid and precise system for lead determination in whole blood.

The paper describes a heated furnace atomic absorption method for determining lead in whole blood using an automated sample introduction system. It is direct and rapid. No sample pretreatment is required and up to 30 samples per hour can be analyzed. Precision and accuracy data are presented. The system has been applied to both macro (venipuncture) and micro (capillary) samples. The method uses physiologically-bound lead standards to compensate for matrix effects. It has been used in the screening of target populations and for confirming elevated blood lead levels in the California Department of Health Services Childhood Lead Program.

Blood Viscosity↗
PubMed1977

Metals as mutagens.

A number of metals are mutagenic in bacteria or phage. These include compounds of arsenic, chromium, copper, iron, manganese, molybdenum, platinum, and selenium. Compounds containing alumium, antimony, arsenic, cadmium, copper, lead, mercury, nickel, and tellium have been shown to induce chromosomal aberrations or abnormal cell divisions in animal or plant cells. Genetic evidence suggests that arsenic, chromium, and molybdenum compounds may influence the accuracy of DNA repair processes in microorganisms.

Animals↗
PubMed1976

Metal-polynucleotide interactions. A comparison of carcinogenic and non-carcinogenic metals in vitro.

The effects of divalent cations on mixing curves of synthetic polyribonucleotides in solution are described. Manganese and cadmium chlorides at 10(-3) M induce changes suggestive of base mispairing. MnCl2 induces mispairing in complexes formed between both poly(I) and poly(C,U) and poly(I) and poly(C,A) while CdCl2 affects base pairing between poly(I) and poly(C,U) only. By contrast, the chlorides of magnesium and zinc show no mispairing effects with either polymer pair. Manganese and cadmium are both reported carcinogens in animals while magnesium and zinc are not. The possibility that direct metal-nucleic acid interaction may be involved in metal carcinogenesis is discussed.

Binding Sites↗
PubMed1967

Polyribosomes of growing bacteria.

A method of extracting polyribosomes has been developed which uses lysozyme on bacteria in the exponential phase of growth. This procedure recovers more than 80 percent of the total ribonucleic acid and nearly all of the soluble protein. Analysis of the lysate on sucrose gradients shows that 80 to 90 percent of the ribosomes sediment with the polysome fractions, indicating little or no degradation. The method has been applied to both a Gram-positive and a Gram-negative organism under various growth conditions and has proved uniformly successful.

Centrifugation, Density Gradient↗
PubMedDate not supplied

The identification and elimination of a potential lead hazard in an urban park.

During development of a park in Oakland, California, a potential public helath hazard due to lead in the soil (approximately 1,000 to 100,000 ppm) was identified through cooperative sampling and analysis efforts of the staffs at the county and state health departments. Analysis of samples collected at various locations and depths in the park, coupled with a three-dimensional model of the lead values obtained, indicated steps necessary to eliminate the hazard. The county undertook the abatement program, and with the elimination of the health hazard, the park development has been completed. Concomitant blood lead screening of neighborhood children failed to establish the park as a source of elevated lead in any of the children tested.

Child, Preschool↗
PubMedDate not supplied

Identification of lead sources in California children using the stable isotope ratio technique.

Two case studies are presented which apply the lead isotope ratio method to the identification of lead sources in 12 Oakland, California children. One study examined lead sources in 10 children, ages 3 to 15 yr, living together as an extended family in dilapidated housing close to a busy freeway. Eight children had elevated blood lead levels (greater than or equal to 30 micrograms/dl) and 6 children also had elevated erythrocyte protoporphyrin levels (greater than or equal to 50 micrograms/dl). A second case study examined 2-yr-old male twins, both with elevated blood lead and erythrocyte protoporphyrin levels, living in a modest, but well maintained inner city duplex apartment. Paint and surface soil samples collected in and around both households had high lead concentrations. Paint concentrations ranged from 2.9 to 273 mg/g and surface soil concentrations from 0.48 to 7.1 mg/g. The isotopic ratios of lead in the blood of these children were close to the average lead ratios of paints from exterior walls and to the lead ratios of surface soils in adjacent areas where the children played. In both case studies, the data suggest that the lead in the soil was derived mainly from weathering of lead-based exterior paints and that the lead-contaminated soil was a proximate source of lead in the blood of the children.

Adolescent↗